Too many things to guess at, but this is a signal that should not be ignored if it persists.
Sounds like a stroke.
GERD
Nausea can occur when input from the vestibular apparatus regarding position or movement differs from what would be expected based on experience. (Motion sickness.)Other stimuli that can cause nausea are:noxious odorsvisual stimulichemotherapy
Adolescence.
yes
Worms usually cause vomiting because it feels there are butterflies in the stomach that cause nausea.
Diverticulitis
a spider bite.
Contraction of the pupillary contrictor muscles.
Drinking seawater would significantly increase the amount of salt in the bloodstream and leads to dehydration. Nausea, weakness and even delirium are the effects of being dehydrated.
Diabetes can cause all of those symptoms
Pregnancy would be a common reason to cause nausea in a girl after sex.